The present invention relates to sprinkler units and pertains particularly to rotating sprinkler heads.
Rotatable sprinkler units or sprinkler heads are extensively used for irrigation purposes because they are capable of covering large areas. This large area of coverage by rotatable sprinkler heads reduces the amount of conduit that is necessary for supplying the water to the area to be irrigated.
One of the major drawbacks to rotary sprinkler heads is the nonuniformity of coverage achieved by the sprinkler head. Any interference with the primary stream of water from the sprinkler head tends to reduce the area of coverage of the sprinkler head. Impact type impulse sprinkler heads are one of the most widely used rotary sprinkler heads today. However, these sprinkler heads, although adjustable to improve coverage, also suffers from the problem of lack of adjustability to provide fairly uniform coverage.
When a sprinkler head is adjusted to provide a very large area of coverage, it tends to supply a greater amount of water to the outer perimeter to the area covered than in the inner area. The angle of the nozzle with the horizon often controls the range (i.e. outer diameter) of coverage. Thus, the higher the angle, within limits, the larger the diameter of the area covered, whereas the lower the angle toward or even below the horizontal, the smaller the area covered.
It is therefore desirable to provide means for providing regular uniform adjustment of the sprinkler unit lift to obtain maximum uniformity of coverage of the area.